Modern hybrid vehicles, which have both an internal combustion engine and an electric motor for powering the vehicle, often comprise a start/stop automatic by means of which the internal combustion engine of the hybrid vehicle is stopped as soon as the hybrid vehicle is standing longer than a predefined time interval in order to thereby save fuel. As soon as the driver subsequently actuates an accelerator pedal of the hybrid vehicle, actuates the clutch, or engages a gear the engine automatically is started up again to further power the hybrid vehicle. Furthermore, it is common practice in modern hybrid vehicles that the internal combustion engine of the hybrid vehicle is started automatically under certain conditions, in particular when the hybrid vehicle detects that the charging condition of its battery is below a predefined threshold value.
In hybrid vehicles, in particular in hybrid vehicles comprising a start/stop automatic for the internal combustion engine, also in a case where the hybrid vehicle is parked and independent of whether a driver of the hybrid vehicle is present or not an automatic startup of the internal combustion engine may occur. In particular this happens when the so called readiness to drive or readiness for operation of the hybrid vehicle has not been disabled and due to a certain condition (e.g. the charging condition of the battery of the hybrid vehicle) the internal combustion engine is activated. On the one hand, by this startup of the internal combustion engine a risk of poisoning is generated when the parked hybrid vehicle resides in a closed room (for example in a garage), and on the other hand an uncontrolled driving of the hybrid vehicle by a third party, for example by children playing in the hybrid vehicle, is possible.
It is known from DE 102 11 463 A1 to monitor the status of the engine hood of the vehicle in a hybrid vehicle and in case that an opening of the engine hood has been detected to inhibit a startup of the internal combustion engine. However, this approach is associated with the problem that in the so called readiness to drive or electric mode in which the internal combustion engine has not yet been started the vehicle may break down in case of a defective engine hood sensor since in that case no startup of the internal combustion engine is possible.